Problems with datalogging wideband O2 sensor

Jack Hidley · Post by **Jack Hidley** » Mon May 12, 2003 1:22 am

The application is a 302 with an A9L ,Tweecer, 1.20B3 software and a Bailey wideband O2. I found the file DIYWB.DBF in the Tweecer directory. I modified the contents of this transfer function to match what my actual wideband transfer function is. In CalCon I selected the DIY O2 sensor. In CalEdit I have tried 0, 1 and 2 for EGR type. The linear output from the Bailey is connected to pin 27 on the EEC (EGR position sensor input). The sensor connector is unplugged from the EGR valve. The wideband O2 reading on the dashboard and in the datalog is about 1-2 afr lower than the actual afr reading from the front of the Bailey. I have checked the actual output from the Bailey with a DMM. The output voltage corresponds with the reading on the front of the Bailey. Any ideas?

Also, is everyone aware that the MAF reading on CalCon in kg/hr is not correct? The datalogs are correct, but the displayed values are completely wrong.

desmo996 · Post by **desmo996** » Mon May 12, 2003 3:07 pm

I don't know anything about the o2, but the MAF display in Calcon, if you also datalog the MAFv, it will display the voltage with the kg/hr appendix. At least it does for me.

Jack Hidley · Post by **Jack Hidley** » Mon May 12, 2003 5:05 pm

Yes, that makes sense. It is displaying voltage, but shows a unit of kg/hr. It does this whether I datalog MAF kg/hr or MAFV. Minor bug.

Jack Hidley · Post by **Jack Hidley** » Thu May 22, 2003 7:57 pm

Mr. Glover are you out there?

gt90stang · Post by **gt90stang** » Thu May 29, 2003 12:19 pm

Jack,

I checked the schematic for an A9L and the EVP input goes straight into an A to D input. There is a filter and load on the input that the output of your WB box will see 0.01uF to ground in parallel with 330K Ohms, then there is a series 3.3K Ohm to a 1uF cap to ground that feeds the A to D input.

Some amplifiers don't like capacitive loads and may oscillate which could give lower readings in your logs. Either scope the output of your WB while connected to the PCM or try inserting a series 100 Ohm to 1K Ohm resistor (not critical) from the output of your WB to the PCM EVP input and see if that helps. You can do this temporarily with jumpers to see if it corrects the problem just keep the leads short and make sure they don't touch anything.

Good Luck, Don

Problems with datalogging wideband O2 sensor

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